docs: complete XML doc comments via fixdocs (2757 to 131 findings)

Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/TwinCATHighFindingsRegressionTests.cs

@@ -20,6 +20,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     // ---- Driver.TwinCAT-001 — Reinitialize applies the new config generation ----
 
     /// <summary>Verifies ReinitializeAsync applies new device configuration at runtime.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task ReinitializeAsync_applies_changed_device_config()
     {
@@ -49,6 +50,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     }
 
     /// <summary>Verifies InitializeAsync applies supplied JSON config over constructor options.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task InitializeAsync_applies_supplied_config_over_constructor_options()
     {
@@ -83,6 +85,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     }
 
     /// <summary>Verifies 64-bit LInt reads preserve values larger than int.MaxValue.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task LInt_read_round_trips_value_above_int_MaxValue()
     {
@@ -107,6 +110,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     // ---- Driver.TwinCAT-007 — concurrent EnsureConnectedAsync creates exactly one client ----
 
     /// <summary>Verifies concurrent reads on one device create and share exactly one client.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Concurrent_reads_on_one_device_create_a_single_client()
     {
@@ -130,6 +134,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     }
 
     /// <summary>Verifies concurrent reads and writes on one device share exactly one client.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Concurrent_reads_and_writes_share_one_client()
     {
@@ -166,6 +171,7 @@ public sealed class TwinCATHighFindingsRegressionTests
     }
 
     /// <summary>Verifies symbol version change events raise the OnRediscoveryNeeded event.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Symbol_version_changed_raises_OnRediscoveryNeeded()
     {